Key Challenges in Cloud Computing to Enable the Future Internet of Services Rafael Moreno-Vozmediano, Rubén S. Montero, and Ignacio M. Llorente Complutense University of Madrid Cloud computing will play a major role in the development of the future Internet of Services, enabling on-demand provisioning of applications, platforms, and computing infrastructures. However, there are several technology challenges that must be addressed to turn this vision into reality. Specific challenges in the deployment of future IaaS clouds include the efficient management of infrastructure clouds to deliver scalable and elastic service platforms on-demand, the development of cloud aggregation architectures and technologies to enable the collaboration and interoperation of cloud providers, and improvements in security, reliability and energy efficiency of cloud infrastructures. The Cross-European Technology Platforms (X-ETPs) Group 1 envisions the Internet of Services (IoS) as one of the key pillars of the Future Internet (see Figure 1). The main target of IoS is to present everything as a service on the Internet, including software applications, the platform to develop and deliver these applications, and the underlying infrastructure (CPU, storage, network, etc.). In this scenario, cloud technology can play an important role as an enabler for IoS deployment, because it comprises different provisioning models for on-demand access to applications (Software as a Service or SaaS clouds), for platforms upon which services and applications can be developed (Platform as a Service or PaaS clouds), and elastic computing infrastructures (Infrastructure as a Service or IaaS clouds). Figure 1. Pillars of Future Internet according to X-ETP vision. The use of these cloud technologies to support IoS offers several benefits: service elasticity through the automatic scaling of services and infrastructures; cost reduction since infrastructure and platform sizes can be adapted to service demands; pay-per-use models that allow the actual consumption of resources to be paid for; improved time-to-market of services from reduced development and infrastructure deploy times; increased availability and reliability of services provided by the replication of service components and rapid deployment of new service instances; cloud interoperability that allows a service to be deployed on multiple clouds, which provides unlimited scalability and optimized service performance. Current cloud market includes several cloud models (IaaS, PaaS, and SaaS), but the infrastructure clouds (IaaS) can be considered as the foundation of future IoS, as shown in Figure 2. As such, future advances on IaaS cloud computing should address the challenges of meeting the requirements of the future Internet, by providing new tools and capabilities for users to deploy and manage their own multi-tier applications and development platforms. Digital Object Indentifier 10.1109/MIC.2012.69 1089-7801/$26.00 2011 IEEE This article has been accepted for publication in IEEE Internet Computing but has not yet been fully edited. Some content may change prior to final publication.